/*
 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
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 *
 *
 *
 *
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 *
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 */
package java.net;

import java.io.IOException;
import java.io.FileDescriptor;
import sun.net.ResourceManager;

/*
 * This class defines the plain SocketImpl that is used for all
 * Windows version lower than Vista. It adds support for IPv6 on
 * these platforms where available.
 *
 * For backward compatibility Windows platforms that do not have IPv6
 * support also use this implementation, and fd1 gets set to null
 * during socket creation.
 *
 * @author Chris Hegarty
 */

class TwoStacksPlainSocketImpl extends AbstractPlainSocketImpl {

  /* second fd, used for ipv6 on windows only.
   * fd1 is used for listeners and for client sockets at initialization
   * until the socket is connected. Up to this point fd always refers
   * to the ipv4 socket and fd1 to the ipv6 socket. After the socket
   * becomes connected, fd always refers to the connected socket
   * (either v4 or v6) and fd1 is closed.
   *
   * For ServerSockets, fd always refers to the v4 listener and
   * fd1 the v6 listener.
   */
  private FileDescriptor fd1;

  /*
   * Needed for ipv6 on windows because we need to know
   * if the socket is bound to ::0 or 0.0.0.0, when a caller
   * asks for it. Otherwise we don't know which socket to ask.
   */
  private InetAddress anyLocalBoundAddr = null;

  /* to prevent starvation when listening on two sockets, this is
   * is used to hold the id of the last socket we accepted on.
   */
  private int lastfd = -1;

  // true if this socket is exclusively bound
  private final boolean exclusiveBind;

  // emulates SO_REUSEADDR when exclusiveBind is true
  private boolean isReuseAddress;

  static {
    initProto();
  }

  public TwoStacksPlainSocketImpl(boolean exclBind) {
    exclusiveBind = exclBind;
  }

  public TwoStacksPlainSocketImpl(FileDescriptor fd, boolean exclBind) {
    this.fd = fd;
    exclusiveBind = exclBind;
  }

  /**
   * Creates a socket with a boolean that specifies whether this
   * is a stream socket (true) or an unconnected UDP socket (false).
   */
  protected synchronized void create(boolean stream) throws IOException {
    fd1 = new FileDescriptor();
    try {
      super.create(stream);
    } catch (IOException e) {
      fd1 = null;
      throw e;
    }
  }

  /**
   * Binds the socket to the specified address of the specified local port.
   *
   * @param address the address
   * @param port the port
   */
  protected synchronized void bind(InetAddress address, int lport)
      throws IOException {
    super.bind(address, lport);
    if (address.isAnyLocalAddress()) {
      anyLocalBoundAddr = address;
    }
  }

  public Object getOption(int opt) throws SocketException {
    if (isClosedOrPending()) {
      throw new SocketException("Socket Closed");
    }
    if (opt == SO_BINDADDR) {
      if (fd != null && fd1 != null) {
                /* must be unbound or else bound to anyLocal */
        return anyLocalBoundAddr;
      }
      InetAddressContainer in = new InetAddressContainer();
      socketGetOption(opt, in);
      return in.addr;
    } else if (opt == SO_REUSEADDR && exclusiveBind) {
      // SO_REUSEADDR emulated when using exclusive bind
      return isReuseAddress;
    } else {
      return super.getOption(opt);
    }
  }

  @Override
  void socketBind(InetAddress address, int port) throws IOException {
    socketBind(address, port, exclusiveBind);
  }

  @Override
  void socketSetOption(int opt, boolean on, Object value)
      throws SocketException {
    // SO_REUSEADDR emulated when using exclusive bind
    if (opt == SO_REUSEADDR && exclusiveBind) {
      isReuseAddress = on;
    } else {
      socketNativeSetOption(opt, on, value);
    }
  }

  /**
   * Closes the socket.
   */
  @Override
  protected void close() throws IOException {
    synchronized (fdLock) {
      if (fd != null || fd1 != null) {
        if (!stream) {
          ResourceManager.afterUdpClose();
        }
        if (fdUseCount == 0) {
          if (closePending) {
            return;
          }
          closePending = true;
          socketClose();
          fd = null;
          fd1 = null;
          return;
        } else {
                    /*
                     * If a thread has acquired the fd and a close
                     * isn't pending then use a deferred close.
                     * Also decrement fdUseCount to signal the last
                     * thread that releases the fd to close it.
                     */
          if (!closePending) {
            closePending = true;
            fdUseCount--;
            socketClose();
          }
        }
      }
    }
  }

  @Override
  void reset() throws IOException {
    if (fd != null || fd1 != null) {
      socketClose();
    }
    fd = null;
    fd1 = null;
    super.reset();
  }

  /*
   * Return true if already closed or close is pending
   */
  @Override
  public boolean isClosedOrPending() {
        /*
         * Lock on fdLock to ensure that we wait if a
         * close is in progress.
         */
    synchronized (fdLock) {
      if (closePending || (fd == null && fd1 == null)) {
        return true;
      } else {
        return false;
      }
    }
  }

    /* Native methods */

  static native void initProto();

  native void socketCreate(boolean isServer) throws IOException;

  native void socketConnect(InetAddress address, int port, int timeout)
      throws IOException;

  native void socketBind(InetAddress address, int port, boolean exclBind)
      throws IOException;

  native void socketListen(int count) throws IOException;

  native void socketAccept(SocketImpl s) throws IOException;

  native int socketAvailable() throws IOException;

  native void socketClose0(boolean useDeferredClose) throws IOException;

  native void socketShutdown(int howto) throws IOException;

  native void socketNativeSetOption(int cmd, boolean on, Object value)
      throws SocketException;

  native int socketGetOption(int opt, Object iaContainerObj) throws SocketException;

  native void socketSendUrgentData(int data) throws IOException;
}
